The shocking 12-story building collapse in the Miami area last week raised questions about the role of the climate crisis, and whether South Florida’s severe vulnerability to rising seas may lead to destabilization of other buildings in the future.
The exact cause of the disaster that hit the Champlain Towers South building in Surfside on Thursday has not yet been fully determined, although a 2018 engineering report on the structure warned of “cracks and major ruptures in concrete ”and that design flaws and deterioration of the waterproofing could cause“ exponential damage ”via the expansion of these cracks.
At the time of the building’s sudden collapse, repairs to its roof were underway, but concrete restoration had not started on the 40-year-old condo. A total of 10 people died from the collapsed building, and 151 people are missing.
The disaster highlighted the precarious situation of the construction and maintenance of high-rise apartments in an area under increasing pressure from sea level rise. Experts say that if the role of the rise of the seas in this collapse is still not clear, the integrity of the buildings will be threatened by the advancing salt water rising from below to weaken the foundations.
“When this building was designed 40 years ago, the materials used would not have been so resistant to saltwater intrusion, which has the potential to corrode the concrete and steel of the foundations,” said Zhong-Ren Peng, professor and director of the University. from the Florida International Center for Adaptation Planning and Design. “Cracks in concrete allow more seawater to enter, causing further reactions and the propagation of cracks. If you do not take care of it, it can cause failure of the structure.
The geography of the area can also prove difficult for construction.
Champlain Towers South was built near the coast of what is a narrow barrier island flanked by the Atlantic Ocean on one side and Biscayne Bay on the other. Such barrier islands naturally change position over time due to the pounding of the ocean, requiring a certain amount of engineering to hold them in place.
Most of South Florida is only a few feet above sea level at a time when the region is experiencing a rapid rise in sea level, due to the man-made climate crisis . To compound this problem, the area relies on limestone, a porous rock that allows rising seawater to bubble from below.
This scenario means Miami residents have become accustomed to flooded car garages and water seeping from drains on the roads, even on sunny days. The city plans to build a major new sea wall to keep the ocean at bay, but there is no simple defense against the water rising underfoot, exposing the foundations of buildings to the risk of being eaten away by water. ‘sea water.
The land under Champlain Towers South is also sagging, which is unusual for eastern Florida, according to a study released last year that found the condo was sagging into the ground at a rate of about 2 mm per year throughout the 1990s. Shimon Wdowinski, a professor at the Institute of the Environment at Florida International University who conducted the research, said he was “shocked” to see the building s’ collapse and did not immediately link it to his study.
“It’s common for us to see buildings with minor sag damage, but not really that,” he said. “Things can go stable and move slowly for a long period of time before suddenly accelerating to the point of collapsing. It is not a linear process.
Peng said building code upgrades in the wake of Hurricane Andrew, a Category five hurricane that hit Miami-Dade County in 1992, made the new structures more resistant to storms. major.
“But older buildings are still under threat and in any case the new building codes may need to be revisited as they do not address the issue of sea level rise,” he said. . “I think at the very least any new development should be required to do a sea level rise impact study before construction is complete. “
The challenge for Miami, however, will continue to escalate.
The region borders seas that are approximately 20 cm higher than a century ago and this rate will accelerate – with an additional 17 cm of sea level expected by 2040. Depending on the melting of the vast ice caps from Greenland and Antarctica, southern Florida could be beset by an additional foot of sea level per decade in the second half of this century, according to Harold Wanless, a geographer at the University of Miami.
“It’s going to be a huge job, if not impossible anywhere to deal with this,” Wanless said. “Sea level rise is accelerating and will do so more dramatically than most people expect.
“Every sand barrier island, every low-lying coast, from Miami to Mumbai, will become flooded and difficult to maintain. You can install gates in sewers and dikes, but the problem is that the water will continue to rise through the limestone. You’re not going to stop it.